Turner Designs TD-20/20 User manual

998-2021 Rev. 1.0 Page 1
TD-20/20 LUMINOMETER SERVICE MANUAL
Rev. 1.0
CONTENTS
Page
Section 1 INTRODUCTION 2
Section 2 PRELIMINARY CHECKS 3
Section 3 TROUBLESHOOTING GUIDE 5
A. Shutter: Mechanical & Electronic 5
B. Injector: Mechanical & Electronic 6
C. Abort Run 7
D. Low/High/Drifting Readings 8
E. No Response (no change in LCD readings) 9
F. High Voltage Alarm (HV bad) 10
G. Power Alarm (Low Pwr) 11
H. Problem with Data Collection (RS-232) 12
I. Keypad 12
J. LCD Blank or Dark 13
K. LCD “Flashing” 13
L. Alarm Condition: General Diagnostic Checkpoints 14
M. Replacing the NVRAM or EPROM 15
Appendix 1 MAIN BOARD LAYOUT 18
Appendix 2 REPLACEMENT PARTS 19

TD-20/20 Luminometer Service Manual
998-2021 Rev. 1.0 Page 2
Section 1
INTRODUCTION
This manual will help you troubleshoot and repair most of the common problems encountered with the TD-
20/20 Luminometer. The User's Manual that came with your instrument contains useful information about
operational parameters, calibration, alarms, and diagnostics; please consult it if you have a problem at this
level.
Materials required:
-Digital voltmeter;
-Standard electronics tools.
1. It has been our experience that what might at first appear to be an electronic failure often turns out to
be operator error, or a loose connector or other simple malfunction. We strongly suggest you check
the simple and obvious things first. (See SECTION 2.)
2. SECTION 3 describes troubleshooting by looking at the symptoms, including cases where an alarm is
triggered.
Section 3L describes general diagnostic checkpoints in alarm conditions.
3. You will find the board layout for locating components and checkpoints in Appendix 1.
4. A parts list for ordering replacement parts can be found in Appendix 2.

TD-20/20 Luminometer Service Manual
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Section 2
PRELIMINARY CHECKS
Troubleshooting should be performed in this sequence:
a. Check for SOFTWARE problems; i.e., make sure operational parameters are correctly set; make sure
sensitivity has been set properly and that level is adequate; check for correct standards, etc., if
applicable.
b. Check for MECHANICAL problems; i.e. correctly installed sample adaptor; sample compartment lid
closed; sample seated correctly in sample holder; injector operational; power supply securely
attached, etc.
c. Finally, perform electronic diagnostics as found in this Service Manual.
If you experience an apparent instrument failure, follow the following steps in order before going on to
SECTION 3.
1. Verify that the power source at your site is working and appropriate for your instrument, i.e., 100 - 240
VAC. Check for blown fuses and check circuit breakers at your site.
2. Make sure the power supply is securely plugged into the socket on the back panel and that the
instrument's power switch is ON.
If the power plug into the unit is loose, then UNPLUG THE UNIT. Take a small screwdriver and insert
it into the slot in the center pin of the power plug socket on the rear panel. Widen the gap so the plug
holds more securely. To test, plug in the unit and turn power switch ON.
Check the instrument's power supply; the green LED on the power supply should be on when
connected to the power source.
3. UNPLUG THE INSTRUMENT FROM THE POWER SOURCE. Remove the instrument from the case:
a. Open the sample compartment lid. Using a 3/32” Allen wrench, remove the 4 screws holding the
lid on. Take off the sample compartment lid.
Be careful not to damage the soft gasket underneath the lid it is important for proper light
seal.
b. Remove the 7 screws on the back panel.
c. Remove the 10 screws from the bottom panel.
d. Lift off the case. CAUTION! Take care not to damage the ribbon cable to the LCD/keypad when
removing the case.

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4. Visually and manually check for loose connectors. The latches on the ribbon cable connectors are
secured as a precaution with RTV, but they have been known to pop open.
Visually and manually check to see that wires are seated in their connectors. The connectors are
secured as a precaution with RTV, but wires have been known to slip out.
Visually and manually check for broken wires.
5. Visually and manually check for loose integrated circuits (IC). Are the IC's snugly pressed into the IC
sockets?
6. Check for any moisture on the printed circuit boards (PCB's) or on the components. If you find
moisture, use a fan to dry the PCB's.
7. Check for corrosion on the PCB's or on the components, including the back side of the PCB.
If corrosion is found:
a. INSTRUMENT MUST BE TURNED OFF!!
b. Use a fine wire brush to remove corrosion.
c. Use isopropyl alcohol to remove any residue.
Note that the areas underneath the components, the sockets and connectors, may be corroded if
there is moisture. The chips on the LCD are especially susceptible to corrosion. If corrosion is
extensive, or if the IC's or sockets are affected, it is probably best to replace the board.
8. Check for burned areas on the PCB's or on the components. If there are black areas (clearly burned)
then components may have to be replaced and/or traces may have to be reconstructed with jumper
wires. Return to the manufacturer. If damage is extensive, it is probably best to replace the board.
9. To retest, reassemble the instrument:
a. Check the sample block at the right rear of the instrument to make sure the large o-ring in the
groove on the top of the block has no nicks or tears and is properly seated.
b. Carefully replace the case of the instrument, paying attention to the LCD/keypad ribbon cable.
c. Loosely replace the 7 screws on the rear panel and the 10 screws on the bottom panel; tighten
them after case is properly aligned.
d. Replace the soft gasket on top of the case over the sample compartment opening; for proper light
seal, make sure it is undamaged.
e. Replace the lid on top of the gasket, aligning it with the screw holes. Replace and tighten the 4
screws using a 3/32” Allen wrench.
10. Plug the instrument in. Turn it on using the power switch on the rear panel. If the instrument still does
not work properly, go on to SECTION 3.

TD-20/20 Luminometer Service Manual
998-2021 Rev. 1.0 Page 5
Section 3
TROUBLESHOOTING GUIDE
A. SHUTTER - MECHANICAL
Note that it is difficult to tell whether a shutter problem is mechanical or electronic, unless you can
see or hear the shutter mechanism operating. Thus, if there is a shutter problem, you will probably
need to check both.
Symptom Problem/Solution
Shutter stops partially closed/open 1. Instrument powered off while shutter was in
motion. To check; power instrument off/on.
2. Improper alignment; return to manufacturer.
Ticking or scratching noise during operation Shutter slightly bent; return to manufacturer.
Shutter does not open or close (stuck) No power or bad connection; return to
manufacturer.
SHUTTER - ELECTRONIC
Symptom:
Shutter does not move when
instrument turned off, then on.
Check for mechanical operation
as in table above. Does it seem
OK?
Action:
Visually check connector M1 (motor
connector) on the Main Board. Make
sure that it is firmly seated. Tug
gently on wires to make sure none
are loose. Any loose connections?
Action:
If shutter itself is bent or
misaligned, contact
manufacturer.
Action:
Fix connections/wires.
Finished.
Action:
Bad M1 connector or shutter
driver circuitry.
Contact manufacturer.
No
No Yes
Yes

TD-20/20 Luminometer Service Manual
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B. INJECTOR - MECHANICAL
Symptom Problem/Solution
Injector cycles but does not pump fluid 1. Tubing fittings loose. Check for leaks; tighten
connections.
2. Valves stuck shut or missing. Remove & inspect
valves as described in Operating Manual.
3. Valve cover not tight. Check for leaks and tighten.
4. Supply or injector tubing or needle plugged.
Clear all tubing; check/replace as required.
5. Bad motor to plunger connection; return to
manufacturer.
Injector leaks fluid at plunger Seal not tight or defective seal; replace tighten seal.
Motor makes noise during injection Motor mounting screws loose. Remove case and check
mounting screws on aluminum standoff posts.
Injector 2 operates when injector 1
selected Motor leads crossed. Remove case to access connectors JP9 and JP10; unplug them and reverse
them.
Valve retainer tightened with reagent clip
bracket interfering; some thread stripping Adjust clip bracket position and retighten.
Motor/plunger motion shakes during
operation Defective motor or bad motor to plunger connection; return to manufacturer.
INJECTOR - ELECTRONIC
Turn the instrument off before removing from case to check any connectors.
*With instrument powered on.
Symptom:
Injector(s) do not operate when
<GO> pushed. Push <GO>*
key. Listen for sound of injector
motor. Can you hear motor
operating?
Action:
Problem is mechanical, with
the injector assembly valves,
fittings, tubing, etc. Carefully
check (see table above) and fix
problem.
Action:
Check connectors JP9 and JP10 on
the Main Board. Make sure that they
are firmly seated. Tug gently on wires
to make sure none are loose. Any
loose connections?
Action:
Fix connections/wires.
Finished.
Action:
Bad connectors or driver
circuitry (U29 or U30).
Contact manufacturer.
No
No
Yes
Yes

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C. “ABORT” RUN
Symptom:
Instrument “aborts” run and
reads >9999; and shutter keeps
clicking. Remove sample and
press <GO> key. Does it abort?
Action:
Sample concentration too high for
current sensitivity setting; lower
instrument sensitivity or dilute
sample.
Action:
Light leak somewhere. Check lid light
seal; check injector(s) tubing, fittings,
valves, etc. for light leaks. Replace as
necessary. If this does not correct
the problem, return to manufacturer.
No
Yes

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D. LOW/HIGH/DRIFTING READINGS
Symptom Problem/Solution
Low reading 1. Sample not mixed completely; all sample not at the bottom of the tube
2. Using auto-injectors: some reagents can stick in injector pump and
tubing, causing interference with chemiluminescent reactions. Clean
injector system thoroughly with distilled water; flush and soak overnight
with 10% bleach in methanol (1 part bleach, 9 parts distilled water, and
90 parts methanol) solution. Flush again with distilled water. If this does
not work, then replace tubing, ferrules, and valves.
3. Using auto-injector:
a. Out of reagent
b. Bubbles in tubing/lines. Prime the injector (you must prime 4 times).
NOTE: Injection volume (250 µL) of the prime is independent of the
injection volume chosen because the full 250 µL is required for adequate
priming.
c. Misaligned needle, causing poor mixing. Check tip of injector needle; if
it is bent or damaged, replace it.
4. If there is no auto injector, and sensitivity is OK, it is possible that there is
a problem with the PMT, signal amplifier circuitry, bad connection from
PMT to main board, or a bad shutter. Check sensitivity level and sample
concentrations first, then contact the manufacturer.
High reading 1. Light leak somewhere. Check:
a. Lid closure and seals
b. Sample compartment plug and injector properly set
c. Injector tubing should be covered by at least 3 inches of opaque shrink
wrap
d. Opaque shrink wrap should be pushed right up to injector needle
adaptor
2. White labels or lab tape used for sample identification can phosphor-esce.
3. Check for sample or reagent spills inside compartment or on window.
High Blank and/or
variable readings Instrument sensitivity may be set too high; set instrument sensitvity and set to 65 - 70%. Setting as high as 85% increases “noise” and may produce
high Blank (up to 3.000) and/or high reading variance (>10% CV).
Drifting reading Chemiluminescence is temperature sensitive. Warm up instrument for same
amount of time before each use and keep ambient temperature constant. 2
hours is enough for instrument to completely equilibrate.

TD-20/20 Luminometer Service Manual
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E. NO RESPONSE (NO CHANGE IN LCD READINGS)
Yes
Yes
Yes
No No
No Yes
No
No Yes
No
Yes
No
Action:
Check the Sen % (HV)
reading on the Diagnostic
Screen. Press <HOME> <8>.
Does it = 0?
Action:
Try setting instrument
sensitivity using light
standard. Does Sen %
still = 0
Action:
Make sure that there is
no jumper across pins
on connector JP2 on
the Main Board. Is
there a jumper?
Remove jumper.
HV should return
to normal.
Symptom:
Readings on LCD do not
change during integration
(no response).
Action:
Open lid slightly.
Does unit "abort" and
display >9999?
Action:
Make sure the shutter
mechanism is working.
Open lid. Turn unit off,
then on while watching
shutter mechanism to
make sure it moves.
Open lid slightly to
avoid too much light
leak. Does it move?
Bad shutter
mechanism.
Contact
manufacturer.
Action:
Unplug the unit! Check
connection JP5 on the
main circuit board. Any
loose connections?
Action:
Fix loose
connection.
Do LCD
readings
respond? If
yes, finished.
Action:
Bad HV
circuitry or
problem with
PMT signal;
contact
manufacturer.
Action:
Sample
concentration too low
for current sensitivity
setting. Increase
sensitivity.

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F. HIGH VOLTAGE ALARM (HV BAD)
No No
Yes
Yes
Yes
No
Symptom:
"HV Bad" alarm; Sen % = 0
Action:
Make sure that there is no
jumper across pins on
connector JP2 on the Main
Board. Is there a jumper?
Remove jumper. HV
should return to
normal.
Action:
Check pin 10 of
connector JP5 on Main
Board. Is it >1.2V?
Action:
Problem with Q1.
Contact manufacturer.
Action:
Bad connection in pre-
amplifier or problem with HV
module or HV monitoring
circuitry. Contact
manufacturer.
Action:
HV driver circuitry
problem. Contact the
manufacturer.
Action:
With the power ON, check
the voltage at JP2 on the
Main Board. Is it >1.5V?